Prefabricated stairs



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United States Patent US. Cl. 52-188 1 Claim ABSTRACT OF THE DISCLOSURE The present invention involves an improved prefabricated stair step arrangement wherein units are provided, each unit including a riser and a tread integrally attached together. The riser and tread each have reinforcing rods which extend from the bottom of the riser up through the riser to the tread and to the rear part of the tread. An L-shaped stair pan in the form of a plate supports the riser and the tread. The rear part of the riser and the bottom of the tread each rest against the pan and are coextensive with it. The edges of the stair pan rest on the supporting rails and bolts extend up through the supporting rails and through the pan into threaded members disposed in openings in the treads.

This invention relates to stairs and, more particularly, to prefabricated stairs.

The construction of stairways in commercial buildings, schools, and the like was heretofore done by a steel contractor and a masonry contractor. Concrete or terrazzo stairways were constructed by fabricating steel pans, attaching them to steel risers by means of carrier angles or other similar structures and placing concrete stair treads on the pans. The pans were attached to the steel risers at the job site. After the pans were bolted to the stringers by the steel erection personnel, the terrazzo or concrete workmen poured the wet terrazzo or concrete substance into the pans. After the concrete had set or the terrazzo had set, it was finished by grinding, polishing, or the like.

As an alternative procedure at present, the terrazzo or concrete workmen attach the precast slabs to the riser and tread pan. Sometimes a nosing which overhangs the riser is then attached to the front of the tread. Thus, there are two separate operations with the known manner of constructing Stairways.

In the present application, the stair risers and carrier angles are attached to the risers after the risers are in place. The concrete treads are then prefabricated in a factory or shop away from the job site and they are bolted to the risers at the carrier angles.

As an alternative, the risers could be made of prefabricated concrete, wood, or the like and the carrier angles attached to them.

It is, accordingly, an object of the present invention to provide an improved stairway.

Another object of the invention is to provide a stairway which is simple in construction, economical to manufacture, and simple and efficient to use.

Still another object of the invention is to provide a prefabricated stairway wherein precast stair treads are attached to carrier angles on risers.

With the above and other objects in view, the present invention consists of the combination and arrangement of parts hereinafter more fully described, illustrated in the accompanying drawing and more particularly pointed out in the appended claims, it being understood that changes may be made in the form, size, proportions, and minor details of construction without departing from the spirit or sacrificing any of the advantages of the invention.

In the drawing:

Patented Sept. 16, 1969 FIG. 1 is a view of a stair tread and steel pan;

FIG. 2 is a view of a stair tread shown with a steel pan and nosings; and

FIG. 3 is a view of another embodiment of the invention.

Now with more particular reference to the drawing and, in particular, FIG. 1, the stairs shown are indicated generally at 10 and they are supported on the stringers 14 which could be steel channels or wood timbers. The stringers 14- have the horizontal carrier angles 15 and vertical carrier angles 21. Horizontal angles 15 have legs 22 that extend horizontally toward each other and form shelves and vertical legs 20 that are welded to the stringers 14. Vertical angles 21 have legs 28 that are welded to the stringers and legs 23 that extend toward each other.

The tread 11 has a top tread surface. The riser 12 is cast integrally with the tread from concrete or the like. The tread is provided with reinforcing wire 17 which extends parallel to the top surface of tread 11 and then down inside the riser 12. Laterally extending rods 24 are set into the concrete to give it lateral reinforcement.

The formed steel pans 16 are formed in the form of an L and have a horizontal part that overlies the horizontal angle 15 and a vertical part that overlies the vertical angle 21. Bolts 18 extend through holes in the angles 15 and through holes in the steel pan 22 and threadably engage fasteners 26 which are cast into the concrete.

A nosing 13 is inset in the front edge of the concrete step as shown.

In the embodiment of the invention shown in FIG. 2, the carrier angle is made in L-shape as in FIG. 1. The carrier angle has vertical angle and horizontal angle 121. Each of these angles has the inwardly extending legs and the L-shaped pan 112 rests on the angles. The pan may be welded so that the horizontal and vertical parts are welded together as indicated generally at 116. The pan 112 is fastened to the angles by means of bolts 118. A tread 111 is formed of a concrete slab with a rein forcing wire 117 embedded therein with laterally extending rods 124. The bolts 118 extend through holes in the angle 121 and engage the treaded members 126 which are cast into the tread 111. A nosing 113 is attached in a recess at the front of the tread and is held in place by the threaded members 119 which have countersunk heads and are threadably received in the members 120 which are embedded in the concrete and precast therein.

In the embodiment of the invention shown in FIG. 3, the stairs 210 have treads 211 and risers 212 integrally cast therewith, which are supported on stringers 214. The stringers have the angle carriers 215 attached thereto and each angle has legs that extend inwardly and support the outer edges of the treads 211 and the risers 212. Reinforcing wire 217 is precast into the treads and risers and reinforcing rods 224 are embedded therein. Bolts 218 extend through holes in the angle carriers 215 and up into threaded fastening members cast in the concrete. The nosings 213 are attached to the front end of the treads and nosing carriers 219 are cast into the concrete.

It will be noted that the stringers 214 may be put into place with the angle carriers 215 attached thereto, thereby forming upwardly facing and forwardly facing surfaces. Then the L-shaped tread and riser combination may be prefabricated in a factory, transported to the job site and placed on the angle carrier 215 and bolted in place by means of bolts 218, thus eliminating casting the treads and risers at the job site.

The foregoing specification sets forth in invention in its preferred practical forms but the structure shown is capable of modification within a range of equivalents.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In combination, stair risers and a plurality of stair treads,

stringers adapted to be supported in inclined relation to a floor with a plurality of said stair treads attached therebetween,

spaced carriers attached to the adjacent sides of said risers and extending inwardly therefrom,

said carriers having a horizontal portion defining an upwardly facing portion and a vertical portion defining surface extending inwardly and upwardly and facing forwardly,

said stair treads having fasteners inibedded therein,

a stair pan formed into an L-shaped having one part horizontal and the other vertical,

said pan resting on said carriers,

said treads resting on said pans,

and said pans underlying and engaging substantially the entire bottom surface of said treads,

and studs extending through said carriers through holes in said pan and threadably engaging said fasteners in said treads,

risers,

one said riser being integrally attached to each said tread,

each said riser having a rear surface disposed at right angles to the bottom of each said tread,

and a front surface inclined downwardly and inwardly,

reinforcing wires disposed in said treads which extend from the lower edge of said risers through said tread to the rear part thereof,

said reinforcing wires being welded to a horizontal portion of said pan and at spaced intervals thereon.

References Cited UNITED STATES PATENTS 863,760 8/1907 Schachner 52190 875,113 12/ 1907 Schachner 52190 893,198 7/ 1908 Schachner 52190 X 1,835,759 12/ 1931 Cook 52188 888,882 5/1908 Grossman 52188 894,801 7/1908 Schachner 52190 947,743 1/ 1910 Steiber 52188 1,069,596 8/1913 Baldry 52-188 1,293,233 2/ 1919 Stewart 52189 1,457,515 6/1923 Frisch 52-190 1,604,117 10/1926 Galvin 52-188 1,655,769 1/1928 Lerner 52--l88 1,745,087 1/1930 Floto 52190 3,290,839 12/1966 Theisen 52-188 FOREIGN PATENTS 475,469 1929 Germany. 261,568 1949 Switzerland.

FRANK L. ABBOTT, Primary Examiner PRICE C. PAW, JR., Assistant Examiner US. Cl. X.R. 52179, 190 

